Variable-speed electric drive for planers.



A. D. DU Bols. VARIABLE SPEED ELECTRIC DRIVE FOR PLANBRS.

APPLICATION FILED JAN. 13,1906.

Patented Mar. 25, 1913.

2 SHEETS-SHEET 1.

A. D. DU 1301s. l VARIABLE SPEED BLEGTRIG DRI-VE OR PLANERS.A-PPLIOATION FILED JAN. 13, 1906. 1,057,045, Patented Mar.2^5,1913.

2 SHEETS-SHEET 2,

l 7W, M4 fly mea-ns whereby a variable speed motor run- 50 f strokeentirely Iindependent of the speed of UNITED sTATEs PATENT oEiijIcE.

ALEXANDER D. DU Bois, or CHICAGO, ILLINOIS, AssIGNOR, DY MEsNEAssIeNiviENTs,

To GENERAL ELECTRIC COMPANY, A CORPORATION or NEW Yom;

. To all -w/wm- #may concern:

' description. 10

'cont-rol for motor driven planers or other My'ii'ivention relates to asystem of speed machines having a reciprocating motion. Itis generallyknown that in the operatic-1 1 Ofj planing machines it is desirable tomaintain .the greatest practicable speed of `return stroke or'backWa-rdtravel `of the 4platen in order to reduce the time of the unproductivepart of` the operat-ion of the planer to aminimum.' -TO thisend thecommon practice'with belt driven planers has' been to soI gear thelmachine that the speed of return :stroke will lbe constant and at itsmaximum permissible -value at,v all times whenl the planer isinoperation, thespeed of return stroke being considerably higher than the'speed of lthe cutting stroke.

i cutting speed of course should be capable of variation, and for thisreason the motor driven planer should be operatedby a variable speedmotor. Heretofore the difficulty of using a variable speed motor fordriving planers has been due to the fact that a variation ofthe motorspeed during the cutting stroke would cause a cha-nge in the speed ofthe return stroke.' It has therefore been the practice tofu'se aconstant speed motor in combination with change gears .for obtainingsev'eral cutting speeds, the platen during the return stroke beingdriven directly through an uncliangeable train of gears'. Thisarrangement is unsatisfactory, since the speed steps obtainable withgears are coarse,-and the means of obtaining them cumbersome anduneconomical of time.

' 'Ilie purpose of my invention is to provide ning always in the samedirectipn can be applied to-a planer and automatically con-l trolled bythe operation thereof in such a manner as v,to make the speed of cuttingreturn stroke, whilev yeither oi'v both can be Specification of LettersPatent.

v V l,Application filed January 13, 1906. Serial No. 295,840.

The

vARIABLEsrEED ELECTRIC DRIVE FOR` :,eIiANEEs.

thus enabled to make the Speed of the return lstroke asv great aspracticable without affecting the speed of the cutting stroke, which maybe varied from a ,low to a. high Patented iam-.25,1913.y

speed according to the work to be done during such stroke, and withoutregard to the speed of the return stroke.

Generally speaking, my invention contemplates tlie use of anon-reversible electric motor for driving the planer o'r other recip`rocatingdevice, a resistance being included in the field circuit of themotor. Independent means are provided for determining the amounts ofsaid resist-ance to'be inserted in the field circuit during the forwardand return strokes, respectively, of the platen of the the strokes. Theplaner, at the end of cutting stroke, is adapted to effect theintroduction into the field circuit of the predetermined amount ofresistance which determines the speed ofthe return stroke, and saidplaner, at .the end kof its return stroke, automatically causes thepredetermined amount. of resistance, which determines the speed of thecutting stroke, to be inserted intothe field circuit. Thus with themotor running continuouslyin one planer, to obtain different speedsfordirection, the planer serves automatically at ,7, each reversal tochange the motorspeed by the interpolation into the circuit ofgone orthe other of said amounts of field resistance, to drive the machine atone speed during the cut and at another speed on the return p L maticview representing the kapplication of my invention to the platen of aplaningmachineg'and Fig. 2 is a diagrammatic View illustrating amodification thereof.

The same letters of'reference'designate the same parts `wherever shown.'

ico

Referring first to 1 I Will describe.:

the application of my invention, its-simplest form, to a p aningmachine: The platen a. f a planeris adapted to be vdriven by'a variablespeed, non-reversible electric -motor Z), and may be reciprocated by a.-.suitable gearing inter osed between the .manner well known in ltheart.

shaft of the motor an the platen in any i l l The field resistance c isincluded in series with the shuntfield F of the motor Z), and is pro-'vided with the movable contact arm (Z con# nected ,by a conductor 1with the conductor connecting the shunt field with resistance c,

`said arm d being adapted to be manually 4resistance c. The/contact fofthe dead' contar;

arin A, with its contacts f set at any desired position along ltheresist-- 4 ance c to determine the amount thereoi toI be included in thefield circuit during the return stroke of the platen, as will behereinafter described. A /similar Contact arm e is provided for theresistance, which is also adapted to be manually set at any desiredposition along the same to determine the resistance to be inserted inthe field circuit during the cutting stroke.'v The arms d, e,

, together with the resistance c, illustrate diagrammatically awell-known form of manually operated rheostat/ The arm'@ Iis connectedby a conductor 2 with 'the contact f of a switch arm A, said arm beingconnected by a conductor 3 with the field circuit between the eld F andthe arm A is connected bya conductor 4 wi the field vcircuit on the sideof the resistance c opposite the field When the arm A is on, .itscontact f, the portion of the resistance" between the arm e andthe endcof the resistance is included inthe field circuit to ob tain the speeddesired for the, cutting stroke '0j the planer. Vhen the arm A is on theContact f the; entire resistance c is short cir- Vcuited, and

the `motor running with its full field strength, and when the arm Afison its ,tyi the portion of the resistance c between ne arm l and thepoint c is included inthe field circuitl to obtain the speed for .thereturn strokeof` the planer, the remaining .portion of .the resistancebeing short circuited by a conductor 1. .Thus the l and f2, comprises aswitch which is adapted to bring about the insertion of thepredetermined -amount of field resistance for the cutting and re.- turnstrokes. Said switch arm may be pivoted at B upon a support C suitablyfastened -to tlie frame'oi the planer, adjacent to the moving platen. aand arranged to be operated by the two pairs of pivoted actuating dogsg/,g and g3, g. g5 and g indicate springs which press the dogs g3 and g4against then' stops. The laten a carries at its |right end the pair ofogs g, g', respectively. As lthe platen a approaches the end of itscutting stroke, traveling in the direction shown by the Aarrow 71 thecentrally pivoted switch arm A being upon its contact f to insert theresistance determined by the arm e into the field circuit, a pin A'carried upon the lower -in the usual manner and portion ofv the lever orswit/ch arm A rides i over the inclined side of the dog g,.depres's iing the same against the tension of thev to prevent sparking. `While themotor is,

runningJ undei these conditions, the motion of the platen aisautomatically reversed in the usual'mannei and the platen commences itsreturn stro-ke. As the platen starts on 'its return stroke, `travelingin the direction in.

dicated by the arrowy h', the dog g again passes overthe pin f withoutoperating t-he lever A, and the en of the dog g engages the pinV A andmoves the arm A over the Contact f and into engagement with its deadcontact f2, thereby. inserting into the field the resistance determinedby the arm d, that the resistance between arm fl' and. the

c. The connections remain undisturbed during the return stro-ke of theplaten,'a-ndl the motor is now running at a speed greater than its speedon the cutting .stroke (unless it' has been set for the same speed asthe speed .of thecutting stroke by,

moving the arm l opposite arm e).

The platen carries at its opposite or left end the other pair ofdogsgjg, respectively, and as the platen; approaches the 'end of itsreturn stroke the pin A2 carried upon the upper'end ofvthe'switch arm Apasses under dog g* withouttouchingit, but engages the end of dog. g3which shiftslthe arm A into engagement` with. its contact f', therebyshort circuiting the resist-ance the motor its full' field strength'`again. When the arm A has reached contact f it is in position to allowthe dog g to pass under the pin A2. The platenl continues its strokefor. a short distance until it is again reversed cutting stroke.

der the piiifA2 but the end of the dog g* enstarts 'back on its,- Thedog g3 again passes un-` c Iand giving gages said pin and the arm A isagain shift ed toits contact f, thereby introducing int-o the fieldcircuitthe resistance determined by the arm e for the cutting stroke. g4will now pass over the pin A, and the platen will continue its cutting.stroke with the portion of the resistance e .toe included in the fieldcircuit of' the motor.

I do not desire to be understood as limit- The dog' ing myself to themeans which I have shown for shifting the position of the switch arm A,since any form of trips lnay be employed forl automatically actuatingthe switch in the movement of the platen. Each set of .dogs may bemounted upon a suitable support c slidably mounted upon the platen a andadapted to be secured in the positions correspondingto the length ofstroke to which the platen has been adjusted.

yReferring now to Fig. 2,1 will describe a modified form of myinventionwhich provides for gradually cutting into the fieldcircui't'the predetermined amounts of resistance for both the cuttingand return strokes. The arms (l and e are preferably mounted upon thesame shaft but insulated from each other. These arms correspond to thearmscl and e, respectively, of Fig. l and are adapted to be set manuallyto determine lthe proper. amounts of resistance to be inserted in thefield circuit for both the cuttingA and return strokes. The arm (l isshown broken off, merely :tor the sake of clearness. The switch arm A'corresponds to the'arin A of Fig.` l, and is adapted to be Aoperated inthe same manner. Said arm is adapted to be moved over a series ofcontacts to be hereinafter described, placed intermediate the maincontacts indicated by the dotted lines. As shown in the drawing, the armA is'resting up-on its contact f so that the entire field resistance isshort circuited by conductorsS, 4, which include the arm Aand itscontact f. The arm A also rests upon the contact. f, which, as shown, is`an extended segment,`and above saidsegnient are provided contacts z',z", 2, which are connected by conductors 5, 6, 7, with different pointsc2, c3. 04, respectively, of resistance c. With this arrangementtheresistance between arm e and point c', which mine the speed of thecutting stroke must be `gradually inserted in the circuit, since theyarm A in traveling over the segment4 f and the contacts C 2, opensshort circuits 5, 6, 7. in sequence about the portions of theresistfance c until the amount determined upon bv the arm e is insertedin the field circuit. Thus with the arm e set to the position shown. assoon as the switchlever A passes the contact 2'. it opens short circuit5, and includes the resistance between the arm e and point c in thefield circuit, and when the switch lever A is moved back to contact fthe resistance is gradually cut out.

lVhen the switch lever A is shifted from' itscentact f to insert theresistance into the field circuit for the return stroke, it engages, vinaddition to the contact f3 connected by conductor 8 with the arm (Z insequence, three contacts Ze, la', 7a2, which are connected by conductors9, 10, 11 with the points c2, cf", c4, respectively, above referred to,of idie resistance c, so that-the predetermined resistance for thereturn stroke, that is, the resistance between arm Z and the point cwill be '.riadl'ially inserted vin the field circuit. Said switch lever,in engaging said contacts, se-

guentially short circuits gradually decreasing portions of theresistance c until the proper amount has-been interpolated into the ieldcircuit. p v 'i i y It will be noted that due to the position of the arme a certain portion of the resistance- 'for the return stroke will havebeen already inserted in the circuit. when the arm A reaches theIcontfvts f, f3 in the path by way of contact f, arm e to point cytlieamount of such `resistance being depend-ent, of course, upon theposition of the arm e. In order to prevent any rei-stlengthening` of thefield by closure of the shortd circuits 9, l0 and 1l, which might beclosed about portions of the resistance c between the arm c and thepoint c', I provide in each of said cond uctors a switch l, which isadapted to be operated by a cam m mounted upon the shaft carrying arm e.The cam thus seveis the continuity of any of the conductors 9, 10, 11,whose points of connection "with resistance c. arel bet-ween the armeandpoint n of said resistance. Thus with the arm e in the position,shown in Fig. 2, the switch Z of conductor 9 will be operated by the camto open such conductor, preventing the short circuiting of the portionof the resistance between the arm e and the point c during theope-ration of gradually weakening the 'field .short circuiting a portionoit the resistance between arm e and point c' by conductor 9, a path forthe" current will l'ai'provided b v way of conductor 9, spring l, cam mand arm e, so that the portion of the resistance between the arm c andthe point c is left in the field circuit while the arm A travels fromits contact f over contact Zr until it reaches contact c, and theportion of the resistance c between points c3, c', is inserted. l/Vhenthe arm A reaches its dead contact f2, it is still in engagement withcontact f3, and the predetermined resistance between .arm l and pointl cof the field resistance is inserted in the field circuit for the returnstroke,

the conductors 3, S, short circuiting the re-l maining portion of theresistance. y

Vhere compound wound motors are used with my system, I provide meanswhereby the series field winding may be utilized to produce a conditionot' greater torque at the end of each stroke oit the platen. To this endI employ a manual switch lever n having Contactl points n', n?,connected to different points along the series field s, said switch armn being connected y conductor 4 inert, and thereby short circuit anydesired series portion ofthe series field, accordingto 'the contactwhich the switch arm n rests upon. The solenoid o 1s included in aconductor 14 extending from the line wire l15 to a contact p, againstwhich the switch arm A rests in engagement with its Contact f', whichisconnected through conductori with the opposite line wire 16. Thus whenthearm A is upon its contact f', the field resistance c is shortcircuited, and the. shunt iield given full strength. At the same timethe switch lever A engages the cont-act p and completes a circuitbetween conductors 15,' 16 for the solenoid o, which separates thecontacts o, withdrawing-the short circuit from the predetermined portionof the series field so that the motor is running with full series fieldstrength and full shunt iield strength. This condition would occur asthe platen approached either limit of its movement, and was about toreverse its direction. IVhen the 'arm A is inengagenient'with itscontacts f2, f3 to insert the predetermined resistance in the shuntfield for the return stroke of the platen, the'circuit of the solenoid-0is interrupted, and the contacts 0 closed, whereu on the redeterminedportion of the eld is s ort'circuited, and the motor running upon aweakened series and shunt field, giving a high speed for the returnstroke,4 Thus at the instant of reversal of the platen, -the motor isrunning as a heavily compounded motor, while during either stroke of theplaten the motor is running`either as a shunt motor or as a lightlycompounded mot-or, according to the position of arm n. By this means Igain the advantage of the heavily compounded motor during the periods ofheaviest load, and the advantage of the good speed' regulation of theshunt or lightly compounded motor during the cutting stroke. v

I claim z 1.. The combination with a reciprocating device, of anelectric motor'for driving the same, a field resistance for the motor,contact arms independent of elch other for determining the amounts ofsaid resistance to be inserted in the forward and backward strokes ofsaid device, a switch operated by said device, and connections wherebysaid switch short circuits the whole field resistance at the end of eachstroke and short circuits a ortion thereof determined by the position othe contact arms at the beginning of each stroke.

2. The combination with a reciprocating device, of an electric motor fordriving the same, a field resistance for the motor, and contact armsmovable independently of each Iother for determining the amount of saidresistance to be inserted in the field circuit during the. forward andbackward strokes of said device, a switch for said resistance, andconnections whereby the switch short circuits the whole field resistancein one posi-- tion of the device and portions of the resistalicedetermined by the position of the contact arms in other positions of thedevice.

3. The combination with a reciprocating device, of an electric motor fordriving the same, a ield resistance for the motor, contact armsindependent of each other for determining the amounts of said resistanceto be inserted in the field circuit during the for-.` A

ward and backward strokesvof said device, a rocking switch lever andcontacts therefor, and actuating dogs carried at opposite endsof saidevice for shifting said lever over its contacts to alternately insertsaid predetermined amounts of field resistance -into ythe field circuitsvduring the strokes of said device. f v In witness whereof, I, hereuntosubscribe my name this 11th day of January A. D., 1906.

ALEXANDER D. DU BOIS. Witnesses:

' ROY T. ALLowav,

BERT 'STARR YORK.

